Combination dry and absorbent floor mop/wipe

ABSTRACT

The present invention provides a single cleaning sheet which allows a user to dry clean a surface with a cleaning sheet that attracts dust, dirt, debris and other particles, while providing absorbency to absorb any cleaning fluid used in a subsequent cleaning operation, in particular for stains and other dirt or debris which is not attracted to the cleaning sheet. The cleaning sheet of the present invention has first side and a second side, the first side is on an opposite side of the cleaning sheet from the second side, wherein the first side has the ability to attract and retain dirt, dust, debris and other particles and the second side has the ability to absorb fluids. Also disclosed in a method of cleaning a surface using the cleaning sheet of the present invention.

FIELD OF THE INVENTION

The present invention relates to a cleaning sheet having a first sidewhich captures and holds dust, dirt debris and other particles and asecond side which is capable of absorbing fluids.

BACKGROUND OF THE INVENTION

Currently, commercially available cleaning sheets are of one of threetypes. These types of cleaning sheets include wet cleaning sheets, drycleaning sheets and absorbent cleaning sheets. Wet cleaning sheetstypically contain a cleaning fluid and are preferably saturated with thecleaning fluid. As a surface is cleaned with the wet cleaning sheet, thecleaning solution is released from the cleaning sheet to solubilize anydirt on the surface to be cleaned so that the wet cleaning sheet canpick-up and retain the dirt. By contrast, a dry cleaning sheet does notcontain any cleaning fluid. Instead, a dry cleaning sheet is one thathas a structure which attracts or retains dirt, dust, debris and otherparticles. In this first type of a dry cleaning sheet, no fluids arenecessary to clean the surface to be cleaned. The absorbent cleaningsheet absorbs and retains liquids applied from a separate source, suchas spray cans, to the surface to be cleaned. The absorbent cleaningsheet is dry until used to absorb and retain liquids.

Many different dry cleaning sheets are known in the art. For example,U.S. Pat. No. 6,245,413 discloses a dry cleaning sheet which attractsdust and retains dust within the structure of the cleaning sheet. Whilethese cleaning sheets attract and retain larger particles from a surfacebeing cleaned, they do not effectively remove dirt physically attachedto the surface to be cleaned. Commercially available dry cleaning sheetsof the first type are available from S.C. Johnson and Sons, Racine,Wis., under the tradename Grab-It™ Dry Cloths and from The Procter andGamble Company, Cincinnati, Ohio, under the name Swiffer™ Dry.

The absorbent cleaning sheet is designed to absorb liquids. For exampleU.S. Pat. Nos. 5,960,508 and 6,101,661 each disclose a cleaning sheetwhich exhibits a controlled rate of fluid absorbency to reduce theamount of cleaning fluid needed to clean a surface. Current commerciallyavailable absorbent cleaning sheets and cleaning implements include theSwiffer™ Wet Jet, available from The Procter and Gamble Company,Cincinnati, Ohio, and the Grab-It™ Go Mop, available from S.C. Johnsonand Sons, Racine, Wis.

Currently, a user desiring to clean a surface with both the attractivedry cleaning sheet and the absorbent dry cleaning sheet would have tohave both dry cleaning sheets and absorbent cleaning sheets readilyavailable. However, having both types of sheets available for cleaningrequires additional storage space, the need to ensure that both sheetsare available at the time of cleaning and the need to have a mop orcleaning implement which is able to retain both types of sheets duringuse. There is not a cleaning sheet available on the market which allowsthe user to effectively clean a surface using both dry attractivecleaning and absorptive cleaning. Therefore, there is a need in the artfor a cleaning sheets which allows a user to dry clean a surface and toabsorb a cleaning fluid using a single cleaning sheet.

SUMMARY OF THE INVENTION

The present invention provides a single cleaning sheet which allows auser to dry clean a surface with a cleaning sheet that attracts dust,dirt, debris and other particles, while providing absorbency to absorbany cleaning fluid used in a subsequent cleaning operation, inparticular for stains and other dirt or debris which is not attracted tothe cleaning sheet. The cleaning sheet of the present invention has afirst surface and a second surface, the first surface is on an oppositeside of the cleaning sheet from the second surface, wherein the firstsurface has the ability to attract and retain dirt, dust, debris andother particles and the second surface has the ability to absorb fluids.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross-section of an exemplary cleaning sheet of thepresent invention.

FIG. 2 shows a cross-section of another exemplary cleaning sheet of thepresent invention.

FIG. 3 shows a cross-section of an exemplary cleaning sheet of thepresent invention, With a barrier layer between the two surfaces.

FIG. 4 illustrates a cleaning implement of the present invention.

DEFINITIONS

As used herein, the term “comprising” is inclusive or open-ended anddoes not exclude additional unrecited elements, compositionalcomponents, or method steps.

As used herein, the term “consisting essentially of” does not excludethe presence of additional materials which do not significantly affectthe desired characteristics of a given composition or product. Exemplarymaterials of this sort would include, without limitation, pigments,antioxidants, stabilizers, surfactants, waxes, flow promoters,particulates and materials added to enhance processability of thecomposition.

As used herein, the term “polymer” generally includes but is not limitedto, homopolymers, copolymers, such as for example, block, graft, randomand alternating copolymers, terpolymers, etc. and blends andmodifications thereof. Furthermore, unless otherwise specificallylimited, the term “polymer” shall include all possible geometricalconfigurations of the material. These configurations include, but arenot limited to isotactic, syndiotactic and random symmetries.

As used herein, the term “fiber” includes both staple fibers, i.e.,fibers which have a defined length between about 19 mm and about 60 mm,fibers longer than staple fiber but are not continuous, and continuousfibers, which are sometimes called “substantially continuous filaments”or simply “filaments”. The method in which the fiber is prepared willdetermine if the fiber is a staple fiber or a continuous filament.

As used herein the term “monocomponent” fiber refers to a fiber formedfrom one or more extruders using only one polymer. This is not meant toexclude fibers formed from one polymer to which small amounts ofadditives have been added for color, anti-static properties,lubrication, hydrophilicity, etc. These additives, e.g. titanium dioxidefor color, are generally present in an amount less than 5 weight percentand more typically about 2 weight percent.

As used herein the term “multicomponent fibers” refers to fibers whichhave been formed from at least two component polymers, or the samepolymer with different properties or additives, extruded from separateextruders but spun together to form one fiber. Multicomponent fibers arealso sometimes referred to as conjugate fibers or bicomponent fibers.The polymers are arranged in substantially constantly positioneddistinct zones across the cross-section of the multicomponent fibers andextend continuously along the length of the multicomponent fibers. Theconfiguration of such a multicomponent fiber may be, for example, asheath/core arrangement wherein one polymer is surrounded by another, ormay be a side by side arrangement, an “islands-in-the-sea” arrangement,or arranged as pie-wedge shapes or as stripes on a round, oval, orrectangular cross-section fiber. Multicomponent fibers are taught in,for example, U.S. Pat. No. 5,108,820 to Kaneko et al., U.S. Pat. No.5,336,552 to Strack et al., and U.S. Pat. No. 5,382,400 to Pike et al.For two component fibers, the polymers may be present in ratios of75/25, 50/50, 25/75 or any other desired ratios.

As used herein the term “biconstituent fiber” or “multiconstituentfiber” refers to a fiber formed from at least two polymers, or the samepolymer with different properties or additives, extruded from the sameextruder as a blend and wherein the polymers are not arranged insubstantially constantly positioned distinct zones across thecross-section of the multicomponent fibers. Fibers of this general typeare discussed in, for example, U.S. Pat. No. 5,108,827 to Gessner.

As used herein the term “nonwoven web” or “nonwoven material” means aweb having a structure of individual fibers or filaments which areinterlaid, but not in an identifiable manner as in a knitted or wovenfabric. Nonwoven webs have been formed from many processes such as forexample, meltblowing processes, spunbonding processes, air-layingprocesses and carded web processes. The basis weight of nonwoven fabricsis usually expressed in grams per square meter (gsm) or ounces ofmaterial per square yard (osy) and the fiber diameters useful areusually expressed in microns. (Note that to convert from osy to gsm,multiply osy by 33.91).

As used herein, the term “meltblowing” or “meltblown” refers to fibersformed by extruding a molten thermoplastic material through a pluralityof fine, usually circular, die capillaries as molten threads orfilaments into converging high velocity heated gas (e.g., air) streamswhich attenuate the filaments of molten thermoplastic material to reducetheir diameters. Thereafter, the meltblown fibers are carried by thehigh velocity gas stream and are deposited on a collecting surface toform a web of randomly dispersed meltblown fibers. Such a process isdisclosed, for example, in U.S. Pat. No. 3,849,241 to Butin, which ishereby incorporated by reference in its entirety. Meltblowing processescan be used to make fibers of various dimensions, including macrofibers(with average diameters from about 40 to about 100 microns),textile-type fibers (with average diameters between about 10 and about40 microns), and microfibers (with average diameters less than about 10microns). Meltblowing processes are particularly suited to makingmicrofibers, including ultra-fine microfibers (with average diameters ofabout 3 microns or less). Meltblown fibers may be continuous ordiscontinuous, and are generally self bonding when deposited onto acollecting surface.

As used herein, the term “spunbond web” or “spunbond” refers to anonwoven web prepared from small diameter fibers of molecularly orientedpolymeric material. Spunbond fibers may be formed by extruding moltenthermoplastic material as filaments from a plurality of fine, usuallycircular capillaries of a spinneret with the diameter of the extrudedfilaments then being rapidly reduced as in, for example, U.S. Pat. No.4,340,563 to Appel et al., and U.S. Pat. No. 3,692,618 to Dorschner etal., U.S. Pat. No. 3,802,817 to Matsuki et al., U.S. Pat. Nos. 3,338,992and 3,341,394 to Kinney, U.S. Pat. No. 3,502,763 to Hartman, U.S. Pat.No. 3,542,615 to Dobo et al, and U.S. Pat. No. 5,382,400 to Pike et al.Spunbond fibers are generally not tacky when they are deposited onto acollecting surface and are generally continuous. Spunbond fibers areoften about 10 microns or greater in diameter. However, fine fiberspunbond webs (having an average fiber diameter less than about 10microns) may be achieved by various methods including, but not limitedto, those described in commonly assigned U.S. Pat. No. 6,200,669 toMarmon et al. and U.S. Pat. No. 5,759,926 to Pike et al., each is herebyincorporated by reference in its entirety.

As used herein, the phrase “bonded carded web” or “bcw” refers to websthat are made from staple fibers which are sent through a combing orcarding unit, which separates or breaks apart and aligns the staplefibers in the machine direction to form a generally machinedirection-oriented fibrous nonwoven web. Such fibers are usuallypurchased in bales which are placed in an opener/blender or picker whichseparates the fibers prior to the carding unit. Once the web is formed,it then is bonded by one or more of several known bonding methods. Onesuch bonding method is powder bonding, wherein a powdered adhesive isdistributed through the web and then activated, usually by heating theweb and adhesive with hot air. Another suitable bonding method ispattern bonding, wherein heated calender rolls or ultrasonic bondingequipment are used to bond the fibers together, usually in a localizedbond pattern, though the web can be bonded across its entire surface ifso desired. Another suitable and well-known bonding method, particularlywhen using bicomponent staple fibers, is through-air bonding.

“Airlaying” or “airlaid web” is a well known process by which a fibrousnonwoven layer can be formed. In the airlaying process, bundles of smallfibers having typical lengths ranging from about 3 to about 19millimeters (mm) are separated and entrained in an air supply and thendeposited onto a forming screen, usually with the assistance of a vacuumsupply. The randomly deposited fibers then are bonded to one anotherusing, for example, hot air or a spray adhesive.

As used herein, through-air bonding or “TAB” means a process of bondinga nonwoven fiber web in which air, which is sufficiently hot to melt oneof the polymers of which the fibers of the web are made, is forcedthrough the web. The air velocity is between 100 and 500 feet per minuteand the dwell time may be as long as 10 seconds. The melting andresolidification of the polymer provides the bonding. Through-airbonding has relatively restricted variability and since through-airbonding requires the melting of at least one component to accomplishbonding, it is generally restricted to webs with two components likemulticomponent fibers or those which include an adhesive. In thethrough-air bonder, air having a temperature above the meltingtemperature of one component and below the melting temperature ofanother component is directed from a surrounding hood, through the web,and into a perforated roller supporting the web. Alternatively, thethrough-air bonder may be a flat arrangement wherein the air is directedvertically downward onto the web. The operating conditions of the twoconfigurations are similar, the primary difference being the geometry ofthe web during bonding. The hot air melts the lower melting polymercomponent and thereby forms bonds between the filaments to integrate theweb.

As used herein, “thermal point bonding” involves passing a fabric or webof fibers or other sheet layer material to be bonded between a heatedcalender roll and an anvil roll. The calender roll is usually, thoughnot always, patterned on its surface in some way so that the entirefabric is not bonded across its entire surface. As a result, variouspatterns for calender rolls have been developed for functional as wellas aesthetic reasons. One example of a pattern has points and is theHansen Pennings or “H&P” pattern with about a 30% bond area with about200 bonds/square inch as taught in U.S. Pat. No. 3,855,046 to Hansen andPennings. The H&P pattern has square point or pin bonding areas whereineach pin has a side dimension of 0.038 inches (0.965 mm), a spacing of0.070 inches (1.778 mm) between pins, and a depth of bonding of 0.023inches (0.584 mm). The resulting pattern has a bonded area of about29.5%. Another typical point bonding pattern is the expanded Hansen andPennings or “EHP” bond pattern which produces a 15% bond area with asquare pin having a side dimension of 0.037 inches (0.94 mm), a pinspacing of 0.097 inches (2.464 mm) and a depth of 0.039 inches (0.991mm). Other common patterns include a diamond pattern with repeating andslightly offset diamonds and a wire weave pattern looking as the namesuggests, e.g. like a window screen. Typically, the percent bonding areavaries from around 10% to around 30% of the area of the fabric laminateweb. Thermal point bonding imparts integrity to individual layers bybonding fibers within the layer and/or for laminates of multiple layers,point bonding holds the layers together to form a cohesive laminate.

As used herein “pattern unbonded” or interchangeably “point unbonded” or“PUB”, means a fabric pattern having continuous bonded areas defining aplurality of discrete unbonded areas. The fibers or filaments within thediscrete unbonded areas are dimensionally stabilized by the continuousbonded areas that encircle or surround each unbonded area, such that nosupport or backing layer of film or adhesive is required. The unbondedareas are specifically designed to afford spaces between fibers orfilaments within the unbonded areas. A suitable process for forming thepattern-unbonded nonwoven material of this invention includes providinga nonwoven fabric or web, providing opposedly positioned first andsecond calender rolls and defining a nip there between, with at leastone of said rolls being heated and having a bonding pattern on itsoutermost surface comprising a continuous pattern of land areas defininga plurality of discrete openings, apertures or holes, and passing thenonwoven fabric or web within the nip formed by said rolls. Each of theopenings in said roll or rolls defined by the continuous land areasforms a discrete unbonded area in at least one surface of the nonwovenfabric or web in which the fibers or filaments of the web aresubstantially or completely unbonded. Stated alternatively, thecontinuous pattern of land areas in said roll or rolls forms acontinuous pattern of bonded areas that define a plurality of discreteunbonded areas on at least one surface of said nonwoven fabric or web.The PUB pattern is further described in U.S. Pat. No. 5,858,515 toStokes et al, the entire contents of which are hereby incorporated byreference.

As used herein, the term “cleaning sheet” or “wiping sheet” is intendedto include any web which is used to clean an article or a surface.Examples of cleaning sheets include, but are not limited to, webs ofmaterial containing a single sheet of material which is used to clean asurface by hand or a sheet of material which can be attached to acleaning implement, such as a floor mop or a hand held cleaning tool,such as a duster.

As used herein, the term “debris” means items which typically needremoval during a cleaning process. This term is intended to include, butis not limited to, hair (both human and pet), dandruff (both human andpet), food particles, e.g. crumbs from bread, cakes, cookies and thelike, grass, dirt, defoliated skin, and other such items.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a single cleaning sheet which allows auser to dry clean a surface with a cleaning sheet that attracts dust,dirt and other particles, while providing absorbency to absorb anycleaning fluid used in a subsequent cleaning operation, in particularfor stains and other dirt or debris which is not attracted to the drycleaning sheet. The cleaning sheet of the present invention has a firstsurface and a second surface, wherein the first surface is on anopposite side of the cleaning sheet from the second surface, and thefirst surface is prepared from a first material which has the ability toattract and retain, dirt, dust and other debris while the second surfaceis prepared from a second material having the ability to absorb fluids.

In order to gain a better understanding of the present invention,attention is directed to FIG. 1. In FIG. 1, a cleaning sheet 100 isshown having a first side 111, prepared from a first material 110, and asecond side 121, prepared from a second material 120. The first surface111 of the cleaning sheet 100 is prepared from a material which has astructure that will have the ability to attract and retain, dirt, dustand other debris. The second surface 121 of the cleaning sheet 100 isprepared from a second material 120 which will absorb fluids.

In another aspect of the present invention, one of both of the first andsecond materials may be a laminate of two or more materials. This isshown in FIG. 2A, which shows a cleaning sheet 200 having a first side211, prepared from a first material which has a structure that will havethe ability to attract and retain, dirt, dust and other debris, and asecond side 221, prepared from a second material 220. The secondmaterial is shown as a laminate of two materials 222 and 224. One orboth of the materials may be absorbent, provided that the overallproperty of the second material 220 is such that the material willabsorb fluids. As is shown in FIG. 2A, the two layers are coextensive.However, as is shown in FIG. 2B, one of the layers may be containedwithin another layer such that one of the layers 222 extends to an outersurface of the cleaning sheet. For example, in FIG. 2B, layer 224 doesnot extend out to the surface of the cleaning sheet.

The first material is a material which has the ability to attract andretain, dirt, dust and other debris. Any material can be used to formthis layer or surface of the cleaning sheet, including woven, knittedand nonwoven materials, provided that the material selected has theability to attract and retain, dirt, dust and other debris. From thestandpoint of cost and properties obtained, the material is desirably anonwoven material.

Exemplary nonwoven materials, commonly called “nonwoven webs” include,nonwoven webs from monocomponent, multiconstituent, or multicomponentfibers. In addition, the shape of the fibers can be round or have adesired shape, such as multilobal fibers. Examples of nonwoven websusable in the dry cleaning layer include, spunbond nonwoven webs,meltblown nonwoven webs, air-laid nonwoven webs and bonded cardednonwoven webs.

The nonwoven webs of the present invention can be prepared from anythermoplastic polymer. The polymers suitable for the present inventioninclude polyolefins, polyesters, polyamides, polycarbonates,polyurethanes, polyvinylchloride, polytetrafluoroethylene, polystyrene,polyethylene terephathalate, biodegradable polymers such as polylacticacid and copolymers and blends thereof. Suitable polyolefins includepolyethylene, e.g., high density polyethylene, medium densitypolyethylene, low density polyethylene and linear low densitypolyethylene; polypropylene, e.g., isotactic polypropylene, syndiotacticpolypropylene, blends of isotactic polypropylene and atacticpolypropylene, and blends thereof; polybutylene, e.g., poly(1-butene)and poly(2-butene); polypentene, e.g., poly(1-pentene) andpoly(2-pentene); poly(3-methyl-1-pentene); poly(4-methyl 1-pentene); andcopolymers and blends thereof. Suitable copolymers include random andblock copolymers prepared from two or more different unsaturated olefinmonomers, such as ethylene/propylene and ethylene/butylene copolymers.Suitable polyamides include nylon 6, nylon 6/6, nylon 4/6, nylon 11,nylon 12, nylon 6/10, nylon 6/12, nylon 12/12, copolymers of caprolactamand alkylene oxide diamine, and the like, as well as blends andcopolymers thereof. Suitable polyesters include polyethyleneterephthalate, polytrimethylene terephthalate, polybutyleneterephthalate, polytetramethylene terephthalate,polycyclohexylene-1,4-dimethylene terephthalate, and isophthalatecopolymers thereof, as well as blends thereof.

Many polyolefins are available for fiber production, for examplepolyethylenes such as Dow Chemical's ASPUN 6811A linear low-densitypolyethylene, 2553 LLDPE and 25355 and 12350 high density polyethyleneare such suitable polymers. The polyethylenes have melt flow rates ing/10 min. at 190° F. and a load of 2.16 kg, of about 26, 40, 25 and 12,respectively. Fiber forming polypropylenes include Exxon ChemicalCompany's ESCORENE PD3445 polypropylene. Many other polyolefins arecommercially available and generally can be used in the presentinvention.

The polymers used to make the nonwoven web may contain additives, suchas surfactants or slip agents, to aid in the sliding of the sensitivesurface against the nonwoven material. Other additives, such aspigments, dyes, processing aids and the like can be added to the polymerprior to fiber formation, provided that the additives do not adverselyaffect the ability of the nonwoven web to pickup and retain dirt, dustand/or debris and/or the ability of the nonwoven web to absorb liquids.Ferroelectric materials, such as those disclosed in U.S. Pat. No.6,162,535 to Turkevich et al, assigned to the assignee of thisinvention, and is incorporated in its entirety by reference, may also beadded to fibers. In addition, other polymeric additives, such as maleicanhydride telomers may also be added, for example to provide electretstability.

The fibers of the nonwoven webs usable in the present invention includemonocomponent fibers, meaning fibers prepared from one polymercomponent, multiconstituent fibers, or multicomponent fibers. Themulticomponent filaments may, for example, have either of an A/B orA/B/A side-by-side configuration, or a sheath-core configuration,wherein one polymer component surrounds another polymer component.

Of these nonwoven webs, spunbond nonwoven webs have been found toeffective in attracting and retaining particles. The fibers produced inthe spunbond process are usually in the range of from about 5 to about50 microns in average diameter, depending on process conditions and thedesired end use for the webs to be produced from such fibers. Forexample, increasing the polymer molecular weight or decreasing theprocessing temperature results in larger diameter fibers. Changes in thequench fluid temperature and pneumatic draw pressure can also affectfiber diameter. The fibers used in the practice of this inventionusually have average diameters in the range of from about 7 to about 35microns, more particularly from about 15 to about 25 microns. Exemplaryspunbond fiber webs usable in the present invention include thosedescribed in U.S. Pat. No. 5,382,400 to Pike et al., U.S. Pat. No.5,874,460 to Keck, U.S. Pat. No. 5,460,884 to Kobylivker et al., U.S.Pat. No. 5,858,515 to Stokes et al., U.S. Pat. No. 5,707,735 to Midkiffet al., and U.S. Pat. No. 6,200,669 to Marmon et al.; the entirecontents of each of the aforesaid references are incorporated herein byreference.

Of these spunbond material describe, the multicomponent crimped fiberspunbond nonwoven webs of Pike et al. very effective in retainingparticles within the nonwoven structure. The fibers used to produce theweb of this invention are multicomponent fibers. As these multicomponentfibers are produced and cooled, the differing coefficients of expansionof the polymers can cause these fibers to bend and ultimately to crimp,somewhat akin to the action of the bimetallic strip in a conventionalroom thermostat. Crimped fibers are described in U.S. Pat. No. 5,382,400wherein fibers are crimped with the same air as is used to draw them.Sufficiently warm drawing air activates the latent helical crimp of thefibers as the fibers are produced and before they are deposited on theforming wire. Crimped fibers have an advantage over uncrimped fibers inthat they produce a more bulky web, thereby increasing the void spacingwithin the nonwoven web. Larger void spacing is a desirablecharacteristic for cleaning sheets, since the larger voids will allowfor the pickup and retention of larger particles of dirt, dust and/ordebris. Therefore, crimped fibers are somewhat more desirable thanuncrimped fibers in cleaning sheets. Additionally, the degree of crimpcan be controlled by controlling the temperature of the drawing air,thereby providing a mechanism for controlling the web density.Generally, a higher air temperature produces a higher number of crimps.This allows one to change the resulting bulk density, and void sizedistribution of the resulting cleaning sheet by simply adjusting thetemperature of the air in the fiber draw unit.

Other nonwoven webs having the ability to attract and retain particlesare nonwoven webs formed from multicomponent, multilobal shaped fibers.These nonwoven webs, describe in U.S. patent application Ser. No.10/021,637, filed Dec. 12, 2001, by Keck et al., which is herebyincorporated by reference, also have an enhanced dirt, dust and/ordebris pickup and retention within the nonwoven web structure. Themulticomponent, multilobal shaped fibers have “lobes” separated bydepressed regions which allow the nonwoven web to attract hold theabsorbed particles in place within the nonwoven structure. Tips of themulticomponent, multilobal shaped fibers increase surface area whichprovides for enhance surface contact, which in turn provides for theenhanced dirt, dust and/or debris pickup of the cleaning sheet. Inaddition, the multilobal shape of the fibers also creates voids withinthe nonwoven web structure which allows for dirt, dust and/or debrisretention within the nonwoven web.

These multicomponent fibers may be split, crimped and through-air bondedamong many other properties and bonding options. Combining theadvantages of the liquid and particle pick-up and retention ofmultilobal fibers with the processing advantages of multicomponent fiberresults in a nonwoven web which has highly desirable properties neededin cleaning sheets. In addition, the fibers of the present inventionhave improved processability and can provide a myriad of differentnonwoven webs having properties which can be tailored to the needs ofthe end user.

Preferred shapes for the multilobal fibers are those described in U.S.Pat. Nos. 5,069,970 and 5,057,368 to Largman et al., assigned to AlliedSignal, Inc., hereby incorporated by reference in their entirety, whichdescribe fibers with unconventional shapes. In addition, shaped fibersare also described in U.S. Pat. Nos. 5,314,743, 5,342,336 and 5,458,963to Meirowitz et al., hereby incorporated by reference in their entirety.In addition, the multicomponent shaped fibers as is shown in U.S. Pat.No. 5,707,735 to Midkiff et al, which is also hereby incorporated byreference in its entirety, may also be used in the first layer of thepresent invention. Fibers having the shapes and configurations of the'735 patent may also be used in the present invention. Generally, themultilobal fibers of the present in invention will have between 2 and 10lobes, but preferably have between 2 and 5 lobes.

In the present invention, the nonwoven web of the first layer willtypically have a bulk density of about 0.01 to about 0.2 g/cm³.Preferably, the cleaning sheets with have a bulk density of about 0.015to about 0.075 g/cm³ and ideally about 0.02 to about 0.05 g/cm³. Inaddition, the nonwoven web of the first layer of the cleaning sheets ofthe present invention may have basis weights ranging from about 0.25 osy(8.5 gsm) to about 25 osy (850 gsm). The actual basis weight of thenonwoven material is dependent of the final use of the cleaning sheet.It is desirable that the basis weight be in the range from about 0.5 osy(17 gsm) to about 10 osy (340 gsm), and preferably about 1.0 osy (34gsm) to about 5 osy (170 gsm), for many applications.

To further enhance the ability of the first layer to attract and retainparticles, the first layer may be subjected to an electret treatment canbe carried out by a number of different techniques. One technique isdescribed in U.S. Pat. No. 5,401,446 to Tsai et al. assigned to theUniversity of Tennessee Research Corporation and incorporated herein byreference in its entirety. Tsai describes a process whereby a web orfilm is sequentially subjected to a series of electric fields such thatadjacent electric fields have substantially opposite polarities withrespect to each other. Thus, one side of the web or film is initiallysubjected to a positive charge while the other side of the web or filmis initially subjected to a negative charge. Then, the first side of theweb or film is subjected to a negative charge and the other side of theweb or film is subjected to a positive charge. Such webs are producedwith a relatively high charge density without an attendant surfacestatic electrical charge. The process may be carried out by passing theweb through a plurality of dispersed non-arcing electric fields whichmay be varied over a range depending on the charge desired in the web.The web may be charged at a range of about 1 kVDC/cm to about 25 kVDC/cmor more particularly about 4 kVDC/cm to about 12 kVDC/cm and still moreparticularly about 7 kVDC/cm to about 8 kVDC/cm.

Electret charge stability can be further enhanced by grafting polar endgroups onto the polymers of the multicomponent fibers. In addition,barium titanate and other polar materials may be blended with thepolymers to enhance the electret treatment. Suitable blends aredescribed in U.S. Pat. No. 6,162,535 to Turkevich et al, assigned to theassignee of this invention and in PCT Publication WO 00/00267 to Myerset al.

Other methods of electret treatment are known in the art such as thatdescribed in U.S. Pat. No. 4,215,682 to Kubik et al, U.S. Pat. No.4,375,718 to Wadsworth, U.S. Pat. No. 4,592,815 to Nakao and U.S. Pat.No. 4,874,659 to Ando, each hereby incorporated in its entirety byreference.

The second surface is prepared from a material which will absorb fluids.Any absorbent material may be used in this layer, including, but notlimited to foams, woven, knitted and nonwoven materials.

The absorbent layer can comprise a material or combination of materialsthat provide good absorbency. The absorbent layer desirably has asubstantially uniform thickness. Additionally, the absorbent layer isdesirably thin yet provides adequate absorbent capacity. Further, theabsorbent layer desirably comprises a material which is wet-resilientand maintains good absorbency after absorption of the cleaning fluid. Inthis regard, the absorbent layer desirably is capable of substantiallyretaining its shape and stiffness when wet in order to prevent bunchingand/or rolling during use. The absorbent layer desirably has anabsorbency (i.e. absorbent capacity) of at least about 5 g/g, and stillmore desirably an absorbency of at least about 15 g/g. In addition, theabsorbent layer desirably has a thickness less than about 1.25 cm andstill more desirably between about 0.3 cm and about 1.25 cm. Further, asindicated above, the absorbent material desirably has a length and/orwidth so as to allow formation of flaps having the desired dimensions.

The absorbent layer, in one aspect, may comprise a mixture or stabilizedmatrix of pulp and substantially continuous thermoplastic fibers and/orthermoplastic staple fibers. The absorbent layer desirably comprises acombination or mixture of thermoplastic fibers and an absorbent materialstructured such that the pulp or other absorbent is substantial held inplace. The absorbent material can comprise coform materials althoughother suitable absorbent fabrics comprising a combination ofthermoplastic fibers and absorbent material may likewise be used inaccord with the present invention. Exemplary coform materials aredisclosed in commonly assigned U.S. Pat. No. 5,284,703 to Everhart etal., U.S. Pat. No. 5,350,624 to Georger et al., U.S. Pat. No. 4,784,892to Maddem et al. and U.S. Pat. No. 4,100,324 to Anderson et al.; theentire contents of each of the aforesaid references are incorporatedherein by reference. The term “coform material” generally refers tocomposite materials comprising a stabilized matrix of thermoplasticfibers and a second non-thermoplastic material. As an example, coformmaterials may be made by a process in which at least one meltblown diehead is arranged near a chute through which pulp and/or other absorbentmaterials are added to the Web while it is forming. Suitable absorbentsinclude, but are not limited to, fibrous organic materials such as woodyor non-woody pulp such as cotton, rayon, recycled paper, wood pulpfluff, cellulose and/or cellulosic staple fibers, and also includeinorganic absorbent materials such as superabsorbent materials and/ortreated polymeric staple fibers. As a particular example, the coformmaterial desirably has a basis weight between about 20 g/m² and about250 g/m² and desirably comprises from about 5% to about 80% by weight ofthermoplastic polymer fibers with the balance being the secondarymaterial, i.e. 20-95 percent by weight. As a specific example, thecoform material can comprise polypropylene meltblown fibers and woodpulp. Generally, the thermoplastic fibers make-up about 30-60% by weightof the absorbent layer and the secondary material, desirably pulp,makes-up about 70-40% by weight of the absorbent layer.

Additional absorbent materials suitable for use in forming the absorbentlayer also include densified pulp products such as, for example, thosedescribed in commonly assigned U.S. Pat. No. 6,368,609 to Fontenot etal. and U.S. Pat. No. 5,779,860 to Hollenberg et al.; the entirecontents of each of the aforesaid references are incorporated herein byreference. In order to achieve improved wet-resiliency, the absorbentlayer desirably comprises a composite structure of pulp andthermoplastic polymer fibers. As a specific example, the absorbent matcan comprise an airlaid composite that is made of pulp fibers and atleast about 2% by weight bicomponent fibers. The pulp fibers aredesirably mixed with the bicomponent fibers in such a way so as toproduce a substantially homogeneous airlaid composite. The bicomponentfibers desirably include a first polymer component and a second polymercomponent wherein the first polymer component melts at a temperaturelower than the melting temperature of the second polymer component. Asan example, the bicomponent fibers can comprise polyethylene/polyester(sheath/core) fibers having a length less than about 1.5 inches (3.81cm) with a denier between about 1.5 to 4. The pulp fibers can have anaverage fiber length of at least about 2 mm, preferably 2-3 mm, and aredesirably present within the composite in the range of about 70-98% byweight of the composite. Various pulp fibers can be utilized including,but not limited to, thermomechanical pulp fibers, chemithermomechanicalpulp fibers, chemimechanical pulp fibers, refiner mechanical pulpfibers, stone groundwood pulp fibers, peroxide mechanical pulp fibersand so forth. After forming the batt, the airlaid composite ispreferably heated such that at least a portion of the first polymercomponent of the bicomponent fibers is melted, thereby bonding thebicomponent fibers to the pulp and bicomponent fibers when cooled.Moisture can then, optionally, added on to the composite to furtherfacilitate bonding when the composite is subsequently subjected tocalendering. The airlaid composite is desirably calendered from aninitial thickness of approximately 0.50 inches to 0.75 inches (1.27-1.91cm) and density of about 0.02-0.05 g/cc. The pulp composite can becalendered or compressed as desired to achieve an absorbent mat havingthe desired thickness and absorbency characteristics. The airlaidcomposite can be calendered before or after incorporation within thecleaning sheet. In one aspect, the pulp composite can be compressed at apressure of about 800 to 4000 pounds per linear inch (pli) (143-715kg/linear cm) to form a thin, calendered airlaid composite having athickness to basis weight ratio of 3.0×10⁻³ mm/1 gsm to 1.0×10⁻³ mm/1gsm, a thickness of 0.025-0.15 cm and a density of 0.1 g/cc or higher.

Desirably, the absorbent layer is a coform material containing between40-70% by weight pulp and 60-30% by weight of a thermoplastic polymer,desirably, polypropylene from the standpoint of cost. Another desirableabsorbent layer is a two layer absorbent coform material having a layerwhich contacts the surface to be clean containing about 30-50% by weightpulp and 70-50% by weight thermoplastic polymer and a second layer,which does not directly contact the surface to be clean containing about60-80% by weight pulp and 40-20% by weight thermoplastic polymer,desirably polypropylene.

The absorbent layer described above may be used alone or in combinationwith another layer, as is shown in FIG. 2. If an additional layer ispresent, the additional layer may also be an absorbent layer.Alternatively, the additional layer may be a layer which protects theabsorbent layer from damage, but allows the cleaning fluid beingabsorbed to pass through the outer layer of the absorbent layer. Thistype of layer is often referred to as a liquid transfer layer.

The liquid transfer layer desirably comprises a highly porous materialthat readily allows and/or facilitates the transfer of liquids in andout of the cleaning sheet. Additionally, the liquid transfer layer alsoneeds to be sufficiently durable and strong to withstand the rigorsassociated with hard surface cleaning. Desirably the liquid transferlayer has a minimum Grab Tensile of about 7 kg. Additionally, the liquidtransfer layer desirably has a minimum abrasion resistance of at least500 cycles (as measured by the Reciprocal Abrasion Test) and still moredesirably has a minimum abrasion resistance of at least 1000 cycles. Inaddition, the liquid transfer layer desirably has a sufficient degree ofopenness to have a Frazier Porosity of at least about 200 cubicfeet/square foot/minute. The liquid transfer layer desirably comprises amaterial having a basis weight below about 64 g/m² and still moredesirably a material having a basis weight between about 15 g/m² andabout 50 g/m². An exemplary material comprises spunbond fiber webs suchas, for example, those described in U.S. Pat. No. 5,382,400 to Pike etal., U.S. Pat. No. 5,874,460 to Keck, U.S. Pat. No. 5,460,884 toKobylivker et al., U.S. Pat. No. 5,858,515 to Stokes et al., U.S. Pat.No. 5,707,735 to Midkiff et al., and U.S. Pat. No. 6,200,669 to Marmonet al.; the entire contents of each of the aforesaid references areincorporated herein by reference. The fibers can be round or have one ormore various shapes such as for example, multilobal, wedge shaped,crescent shaped, ribbon shaped and so forth. In addition, perforatedfilms and fabrics are also well suited for use as or in the liquidtransfer layer. Exemplary perforated nonwoven fabrics include, but arenot limited to, those described in U.S. Pat. No. 5,858,504 to Fitting,U.S. Pat. No. 5,188,625 to Van Iten et al., U.S. Pat. No. 5,620,779 toLevy et al., U.S. Pat. No. 3,949,127 to Ostermeier et al. and U.S. Pat.No. 4,154,885 to Tecl et al.; the entire contents of each of theaforesaid references are incorporated herein by reference. In addition,highly porous or open fabrics having varied or irregular surfaces, e.g.projections or undulations, are also believed suitable for use in thepresent invention. Exemplary materials of this type include, but notlimited to, those described in U.S. Pat. No. 4,741,941 to Englebert etal., U.S. Pat. No. 4,970,104 to Radwanski and U.S. Pat. No. 5,643,653 toGriesbach et al.; the entire contents of each of the aforesaidreferences are incorporated herein by reference. Further, the liquidtransfer layer can comprise an apertured film. Apertured films believedsuitable for use with the present invention and methods of making thesame are described in U.S. Pat. No. 4,280,978 to Danhiem et al., U.S.Pat. No. 5,370,764 to Alikhan and U.S. Pat. No. 5,262,107 to Hovis etal. In addition, the liquid distribution layer can comprise multilayerlaminates of two or more of materials. As a particular example, theliquid distribution layer can comprise an apertured film/nonwoven weblaminate. Desirably, the liquid transfer layer is a PUB spunbondmaterial.

An additional layer may be present in the cleaning sheet. A liquidbarrier layer may be positioned between the first layer and the secondlayer, to prevent the cleaning fluid being absorbed from getting intothe first layer or the dry cleaning layer. Attention is directed to FIG.3, which shows cleaning sheet 101 having a barrier layer 130, positionbetween the first layer 110 and the second layer 120.

The barrier layer desirably comprises a material that substantiallyprevents the transmission of liquids under the pressures and chemicalenvironments associated with surface cleaning applications. Desirably,the liquid barrier layer comprises a thin, monolithic film. The filmdesirably comprises a thermoplastic polymer such as, for example,polyolefins (e.g., polypropylene and polyethylene), polycondensates(e.g., polyamides, polyesters, polycarbonates, and polyarylates),polyols, polydienes, polyurethanes, polyethers, polyacrylates,polyacetals, polyimides, cellulose esters, polystyrenes, fluoropolymersand so forth. Desirably the film is hydrophobic. Additionally, the filmdesirably has a thickness less than about 2 mil and still more desirablybetween about 0.5 mil and about 1 mil. As a particular example, theliquid barrier layer can comprise an embossed, polyethylene film havinga thickness of approximately 1 mil.

In addition, one or more of the polymeric components within the cleaningsheet can contain minor amounts of compatibilizing agents, colorants,pigments, optical brighteners, opacifying agents, ultraviolet lightstabilizers, antistatic agents, wetting agents, additives for improvingabrasion resistance, nucleating agents, fillers and/or other additivesand processing aids. As an example, the liquid barrier layer can containopacifying agents, e.g. TiO₂, in order to provide a white, substantiallyopaque film.

The layers of the cleaning sheet are bonded together using any suitablemeans, such as adhesive bonding, thermal bonding, ultrasonic bonding,mechanical stitching and the like. Desirably, thermal bonding is used.

As indicated herein above, the cleaning sheets of the present inventionare well suited for use with a variety of cleaning equipment and, moreparticularly, are readily capable of being releasably-attached to thehead of a cleaning tool. As used herein, “releasably-attached” or“releasably-engaged” means that the sheet can be readily affixed to andthereafter readily removed from the cleaning tool. In reference to FIG.4, cleaning tool 240 can comprise handle 248, head 244 and fasteners246. Cleaning sheet 243 can be superposed with and placed against head244. Flaps 247 can then be wrapped around head 244 andreleasably-attached to head 244 by fasteners 246, e.g. clamps. Withcleaning sheet 243 affixed to head 244, cleaning tool 240 can then beused. As examples, the size and/or shape of the handle can vary, thehead can be fixed or moveable (e.g. pivotable) with relation to thehandle, the shape and/or size of the head can vary, etc. Further, thecomposition of the head can itself vary, as but one example the head cancomprise a rigid structure with or without additional padding. Inanother configuration, the one of the layers of the cleaning sheet mayextend pass the cleaning surface, thereby forming wings flaps 247. Thesewing or flaps may have different shapes and may be used to attach thecleaning sheet using a suitable means described above. Further, themechanism(s) for attaching the cleaning sheet can vary and exemplarymeans of attachment include, but are not limited to, hook and loop typefasteners (e.g. VELCRO fasteners), clamps, snaps, buttons, flaps,cinches, low tack adhesives and so forth.

In using the cleaning sheet of the present invention, the surface to becleaned is first wiped with the first side, the dry cleaning side. Thewill cause the dust, dirt or other loose debris to be trapped into thedry cleaning portion of the cleaning sheet. Once the surface is wipedwith the dry cleaning portion of the cleaning sheet, the cleaning sheetis then turned over and the absorbing side of the cleaning sheet is usedto absorb and cleaning fluid applied to the surface to be cleaned,thereby removing any dirt or stains physically attached to the surfaceto be cleaned.

EXAMPLES

Various wipe concepts of the present invention were prepared. A 1 ounceper square yard ((osy), 33.9 grams per square meter, (gsm)) prepared inaccordance with U.S. Pat. No. 5,858,515 to Stokes was unwound onto aforming wire. Applied to this spunbond material is coform having amixture of about 50% by weight pulp and 50% weight polypropylene,prepared in accordance with U.S. Pat. No. 4,100,324 to Anderson. Thelayers were thermally bonded together and the resulting cleaning sheethad a basis weight of about 250 gsm (7.4 osy).

A high loft spunbond, having a basis weight of 61 gsm (1.8 osy) preparedin accordance with U.S. Pat. No. 5,382,400 to Pike was unwound and placeonto a forming wire. On to the high loft spunbond, a first layer ofcoform having a mixture of about 70% by weight pulp and 30% weightpolypropylene, prepared in accordance with U.S. Pat. No. 4,100,324 toAnderson was placed. On the first layer of coform a second layer ofcoform was deposited having a mixture of about 50% by weight pulp and50% weight polypropylene, prepared in accordance with U.S. Pat. No.4,100,324 to Anderson. The layers were thermally bonded together and thecleaning sheet had a basis weight of about 310 gsm (9.1 osy).

A high loft spunbond, having a basis weight of 61 gsm (1.8 osy) preparedin accordance with U.S. Pat. No. 5,382,400 to Pike was unwound and placeonto a forming wire. On to the high loft spunbond, a first layer ofcoform having a mixture of about 70% by weight pulp and 30% weightpolypropylene, prepared in accordance with U.S. Pat. No. 4,100,324 toAnderson was placed. On the first layer of coform a second layer ofcoform was deposited having a mixture of about 40% by weight pulp and60% weight polypropylene, prepared in accordance with U.S. Pat. No.4,100,324 to Anderson. The layers were thermally bonded together and thecleaning sheet had a basis weight of about 161 gsm (4.7 osy).

Each cleaning sheet was used to clean a surface by first using thespunbond side of the cleaning sheet to remove particles and the reverseside of the sheet was used to absorb cleaning fluid used to clean thesurface after the particles were removed. Each cleaning sheet exhibitedgood properties for dry cleaning and absorbing a cleaning fluid anddirt. In addition, the PUB layer in the first sample provided a loopmeans to attach the cleaning sheet to an implement having hooks.

While the embodiments of the invention described herein are presentlypreferred, various modifications and improvements can be made withoutdeparting from the spirit and scope of the invention. The scope of theinvention is indicated in the appended claims, and all changes that fallwithin the meaning and range of equivalents are intended to be embracedtherein.

1. A cleaning sheet comprising a first side and a second side, whereinthe first side is on an opposite side of the cleaning sheet from thesecond side, the first side comprises a first material which has astructure with the ability to attract and retain, dirt, dust and otherdebris and the second side comprises a material which has the ability toabsorb fluids.
 2. The cleaning sheet of claim 1, wherein the firstmaterial comprises a nonwoven web and the second material comprises anonwoven web.
 3. The cleaning sheet of claim 2, wherein the nonwoven webcomprises monocomponent, multiconstituent and/or multicomponent fibers.4. The cleaning sheet of claim 3, wherein the nonwoven web of the firstmaterial comprises a nonwoven web selected from the group consisting ofspunbond nonwoven webs, meltblown nonwoven webs, air-laid nonwoven websand bonded carded nonwoven webs.
 5. The cleaning sheet of claim 4,wherein the first material comprises a spunbond nonwoven web.
 6. Thecleaning sheet of claim 5, wherein the spunbond fibers comprisemulticomponent fibers.
 7. The cleaning sheet of claim 1, wherein thesecond material comprises a nonwoven web.
 8. The cleaning sheet of claim71 wherein the second material nonwoven web comprises a nonwoven webcomprising a mixture of thermoplastic fibers and an absorbent material.9. The cleaning sheet of claim 8, wherein In the absorbent materialcomprises pulp and/or a superabsorbent material.
 10. The cleaning sheetof claim 9, wherein the thermoplastic fibers comprise between 5% and 80%by weight of the thermoplastic polymers and between 95% and 20% byweight of pulp and/or the superabsorbent.
 11. The cleaning sheet ofclaim 10, wherein the first material comprises a spunbond nonwoven web.12. The cleaning sheet of claim 1, further comprising a barrier layerpositioned between the first layer and the second layer.
 13. Thecleaning sheet of claim 12, wherein the barrier layer comprises a film.14. The cleaning sheet of claim 1, wherein the second surface comprisesa laminate of at least two materials.
 15. The cleaning sheet of claim14, wherein the second side comprises an absorbent layer and a liquidtransfer layer.
 16. The cleaning sheet of claim 15, wherein theabsorbent layer comprises between 5% and 80% by weight of thethermoplastic fibers and between 95% and 20% by weight of pulp and/orthe superabsorbent and the liquid transfer layer comprises a spunbondnonwoven web.
 17. The cleaning sheet of claim 1, wherein the first sidecomprises a spunbond nonwoven web and the second side comprises anabsorbent layer and a liquid transfer layer, the absorbent layercomprises between 5% and 80% by weight of the thermoplastic fibers andbetween 95% and 20% by weight of pulp and/or the superabsorbent and theliquid transfer layer comprises a spunbond nonwoven web.
 18. A cleaningimplement comprising: a. a handle; b. a head; and c. a removablecleaning sheet, wherein head is connected to the handle, the removablecleaning sheet is removable attached to the head and the removablecleaning sheet comprises the cleaning sheet of claim
 1. 19. A cleaningimplement comprising; a. a handle; b. a head; and c. a removablecleaning sheet; wherein head is connected to the handle, the removablecleaning sheet is removable attached to the head and the removablecleaning sheet comprises the cleaning sheet of claim
 17. 20. A method ofcleaning a surface, comprising wiping the surface with the first side ofthe wipe of claim 1, applying a cleaning fluid to the surface, an wipingthe surface with the second side of the cleaning sheet of claim 1 toabsorb the cleaning fluid applied to the surface.